Oxygen blowing lance fixing device for metallurgical refining furnaces



N 1965 TAKAYUKI IMAIDA ETAL 3,216,713

OXYGEN BLOWING LANCE FIXING DEVICE FOR METALLURGICAL REFINING FURNACESFil ed Nov. 21, 1961 2 Sheets-Sheet 1 FIG 2' FIG Tokoyuki lmuida 1Takclshi Arirna mvsru-roas BY M M ATTORNEYS v- 1965 TAKAYUKI IMAIDA ETAL3,216,713

OXYGEN BLQWING LANCE FIXING DEVICE FOR METALLURGICAL REFINING FURNACES 2Sheets-Sheet 2 Filed Nov. 21. 1961 Takoyuki Imoido Takoshi ArimaINVENTORS I BJ MWM ATTORNEYS United States Patent M 3,216,713 OXYGENBLOWING LANCE FIXING DEVICE FOR METALLURGICAL REFINING FURNACES TakayukiImaida and Takashi Arima, Yawata, Japan, assignors to Yawata Iron &Steel C0., Ltd., Tokyo, Japan Filed Nov. 21, 1961, Ser. No. 153,982Claims priority, application Japan, Dec. 2, 1960, 35/47,630 Claims. (Cl.266-34) This invention relates to an improvement in a device formounting an oxygen blowing lance used in a steel making method employingpure oxygen, and more particularly to an improvement in a device formounting an oxygen blowing lance on an oxygen top-blowing converter andan open-hearth furnace.

Recently, the use of pure oxygen for quickly and efficiently refiningthe steel in a converter or open-hearth furnace has been developedextensively. The development of a highly efficient oxygen top-blowingconverter has been particularly striking. When blowing pure oxy gen ontothe molten pig iron in an oxygen top-blowing converter by means of alance, however, it is necessary to be able to insert the lance freelyinto the converter in a downward vertical direction and pull it upagain. Generally, while blowing oxygen onto the surface of the moltenpig iron in a converter, slag will be deposited on the part of the lanceinserted into the converter. Therefore, in order to be able to pull thelance up through the hood provided at the mouth of converter with slagdeposited thereupon, an aperture must be provided in the upper part ofthe hood which is large enough to afford sufiicient clearance betweenthe lance and the periphery of said aperture for permitting the lanceand slag to pass through freely. However, such an aperture would permitthe high temperature gas produced in the converter to blow off violentlythrough said clearance, and thereby deterioration of the lance fixingdevice or the lance pulling-up device will be hastened. Moreover, as thelance is quite long and the high pressure oxygen is jetted through thelance at a high speed, a violent oscillation of the lance isunavoidable.

To meet these disadvantages the following measures have been taken inconventional methods and apparatus. For instance, to prevent the hightemperature gas from violently blowing off through the aperture, a gascurtain of a high pressure gas such as compressed air or steam has beenformed in the aperture, but such a high pressure gas curtain causes anintolerable noise which makes the operation practically impossible.Moreover, when recovering the waste gas from the oxygen top-blowingconverter in the unburnt state, the sealing gas escaping from the gascurtain forming device will be mixed with the unburnt gas, so that thequality of recovered waste gas will be lessened. Further, to prevent theoscillation of the lance, a fixing device has been provided inconventional methods and apparatus, in which, for instance, laterallymovable rollers or holders are advanced or retracted by an air cylinderor the like so that the lance can be fixed at the desired position.However, in the conventional methods of fixing the lance, devices of alarge size are usually needed and the prevention of leakage of gasesproduced in the converter is not effected by these devices.

A principal object of the present invention is to provide a simple lancefixing device secured around the lance aperture made in the top of aconventional open-hearth furnace or the hood of an oxygen top blowingconverter so that the oxygen blowing lance can be securely fixed and thewaste gas produced in the furnace can be effectively prevented fromleaking out through said aperture.

A further object of the present invention is to provide 3,216,713Patented Nov. 9, 1965 a lance fixing device in which a gas is blown intothe device under pressure to prevent the waste gas produced in thefurnace from leaking out.

The other objects of the present invention will be understood from thefollowing detailed explanation and the accompanying drawings.

FIGURE 1 is a vertical sectional view of an embodiment of the presentinvention.

FIGURE 2 is a cross-sectional view on line AA in FIGURE 1.

FIGURES 3, 4 and 5 are vertical sectional views of the other embodimentsof the present invention.

The present invention shall be described in detail with reference to theembodiments illustrated in the drawings.

In FIGURE 1, 1 is an oxygen blowing lance, 2 is an inner sealing ring, 3is a hanger fixed on the lance 1, 4 is a suspension cable for the innersealing ring 2, 5 is an outer sealing ring for receiving the innersealing ring 2, 6 designates one of a plurality of securing bolts forthe outer ring 5, and 7 is a hood or cover provided in the furna'ce portof the top blowing converter. The outer ring 5 is fixed around anopening port in the hood. The inside surface of the hole in said ringhas an upwardly diverging taper and the outside surface of said innersealing ring 2 has an upwardly expanding taper and its surface contactsthe inside surface of outer ring 5 and is smooth so that the inner ring2 is in closed gas tight contact with the inside surface of the outerring 5 due to its own weight. The inside surface of the hole in theinner ring 2 fits closely around the lance 1 so that the lance can riseand fall freely and oscillation of the lance will not occur and theleakage of the gas produced in the converter may be effectivelyprevented, since the inner sealing ring 2 is made comparatively thick inthe vertical direction.

The suspension cable 4 is connected at its upper end to the hanger 3fixed to the lance and is fastened at the lower end to the inner sealingring 2. The suspension cable 4 may be a wire rope, chain, coil orbellows. It is preferably flexible. The hanger 3 is fixed on the lance 1at a position which permits the lance to go up and down in the converterfreely and the hanging wire has a length such that the inner sealingring 2 fits tightly into the outer ring 5 when the lance is put downinto the converter and it is pulled up out of outer ring 5, before thepart of the lance on which slag is deposited reaches the inner sealingring 5 when the lance is pulled up. That is to say, the length of thesuspension wire is a little longer than the distance between the hanger3 and the inner sealing ring 2 when the lance is in its normal position,so that the inner sealing ring 3 will fit into the outer ring 5 when thelance is put down, but it will not be so long that the inner ring 2 willnot be pulled out of outer ring 5 before the slag on the lance hits thering 2 when pulling up the lance.

By the above described structure of the device according to the presentinvention the lance is securely fixed in the converter, the positioningof the lance in the converter can be controlled and the leakage of gasesproduced in the converter can be effectively prevented. Moreover, thisdevice has the advantage that it is very simple and accordingly no largeinstallation space is needed.

The same device may also be applied to an open-hearth furnace withoutadding any special element. The only difference is that when applyingthis device to an openhearth furnace it is not necessary to pull up thelance each time the tapping is carried out as in the case of aconverter. The lance is pulled up onlywhen it is worn and to berepaired. However, when this is done the same advantages are obtained asin a top-blowing converter.

3 FIGURE 3 shows an embodiment in which a flexible bellows 12 somewhatlonger than the suspension cable 4 is provided outside or inside thesuspension cables 4 between the inner sealing ring 2 and the hanger 3 ina structure otherwise the same as that of FIGURE 1 so that even theslight amount of waste gas leaking out through the clearance between thelance 1 and the airtight ring 2 cannot escape to the atmosphere.

In such case, the suspension cable 4 can be omitted.

FIGURE 4 shows an embodiment wherein the amount of the leakage of thegas is required to be smaller than in the case of FIGURE 1 and ametallic labyrinth 8 is provided inside the inner sealing ring 2 so thatthe leakage of the gas through the clearance between it and the lance 1may be reduced to an amount as small as possible.

Further, the suspension of the inner ring 2 is by means of a coil spring13 and no specific suspension cable is required.

FIGURE shows a further embodiment in which the outer sealing ring 5 ishollow and sealing gas inlet pipes 9 are provided on the outside of saidhollow outer ring 5. A proper number of elliptic holes 10 is provided onthe inside surface thereof opposed to the inner sealing ring 2 and alsoa proper number of elliptic holes 11 communicating with said holes 10 isprovided through said inner sealing ring 2. A metallic labyrinth 8 isprovided in the upper part of the inside of the ring 2 facing thelance 1. The sealing gas introduced through a sealing gas inlet pipe 9will be introduced into the inside of the outer ring 5 and will then bedischarged into a space formed by the inner sealing ring 2 and the lance1 through the communicating holes 10 and 11.

In this embodiment, a part of the gas will go upward along the lance 1and will escape along the lance 1 outward of the inner sealing ringwhile being obstructed by the labyrinth 8, but the greater part of thegas will go downward along the lance 1 and will be jetted into thefurnace gas, so that the furnace gas can be prevented from entering theinside of the inner sealing ring 2 along the lance 1.

What we claim is:

1. An apparatus for mounting an oxygen blowing lance for use in anapparatus for refining steel, comprising an outer sealing ring adaptedto be secured around an aperture provided in the upper part of acovering over the apparatus through which aperture the lance may go upand down freely, said outer sealing ring having an inside surface whichis upwardly diverging, an inner sealing ring having an outside surfacewhich is upwardly diverging and which fits tightly with the insidesurface of said outer sealing ring, said inner sealing ring having acentral bore therethrough, a lance extending through the bore close tothe surface of said inner ring which defines said bore, a hanger fixedto the lance at a position above said inner ring, flexible suspensionmembers mounted at the upper end on said hanger and connected at thelower end to said inner ring and connecting the hanger and the innerring so that said inner ring is pulled up out of said outer ring by saidsuspension members when said lance is withdrawn from the aperture in thecovering.

2. An apparatus as claimed in claim 1 in which said hanger is fixed tosaid lance sufiiciently far above said inner sealing ring when saidlance is in the normal position that said lance can move up and down inthe apparatus, and said suspension members are wires having alength'suficient to pull said inner ring out of said outer ring before aslag covered end of said lance reaches the position of said outer ringwhen the lance is being withdrawn.

3. An apparatus as claimed in claim 1 in which said flexible suspensionmember is a coil spring, and said surface of said inner ring whichdefines said bore has a labyrinth structure therein at the lower endthereof.

4. An apparatus as claimed in claim 1 and a bellows connected betweensaid hanger and said inner sealing ring for sealing off the escape ofgases escaping through the inner sealing ring.

5. An apparatus as claimed in claim 1 in which said outer sealing ringhas an annular hollow interior, an inlet pipe connected to said outerring opening into said hollow interior for admitting a sealing gas intosaid hollow interior, said outer sealing ring having a plurality ofholes therein opening through the inside surface thereof, and said innersealing ring having a plurality of holes therein extending therethroughfrom the outside surface thereof to the inside surface thereof andcommunicating with said holes in said outer sealing ring for conductingsealing gas to the interior of said inner sealing ring.

References Cited by the Examiner UNITED STATES PATENTS 1,205,611 11/16Ford 26634 X 3,025,047 3/62 Reinfeld et al. 26634 3,071,363 l/63 Mackay266-41 WHITMORE A. WILTZ, Primary Examiner.

MARCUS U. LYONS, Examiner.

1. AN APPARATUS FOR MOUNTING AN OXYGEN BLOWING LANCE FOR USE IN ANAPPARATUS FOR REFINING STEEL, COMPRISING AN OUTER SEALING RING ADAPTEDTO BE SECURED AROUND AN APERTURE PROVIDED IN THE UPPER PART OF ACOVERING OVER THE APPARATUS THROUGH WHICH APERTURE THE LANCE MAY GO UPAND DOWN FREELY, SAID OUTER SEALING RING HAVING AN INSIDE SURFACE WHICHIS UPWARDLY DIVERGING, AN INNER SEALING RING HAVING AN OUTSIDE SURFACEWHICH IS UPWARDLY DIVERGING AND WHICH FITS TIGHTLY WITH THE INSIDESURFACE OF SAID OUTER SEALING RING, SAID INNER SEALING RING HAVING ACENTRAL BORE THERETHROUGH, A LANCE EXTENDING THROUGH THE BORE CLOSE TOTHE SURFACE OF SAID INNER RING WHICH DEFINES SAID BORE, A HANGER FIXEDTO THE LANCE AT A POSITION ABOVE SAID INNER RING, FLEXIBLE SUSPENSIONMEMBERS MOUNTED AT THE UPPER END ON SAID HANGER AND CONNECTED AT THELOWER END TO SAID INNER RING AND CONNECTING THE HANGER AND THE INNERRING SO THAT SAID INNER RING IS PULLED UP OUT OF SAID OUTER RING BY SAIDSUSPENSION MEMBERS WHEN SAID LANCE IS WITHDRAWN FROM THE APERTURE IN THECOVERING.